New Kitchen and Old Subfloor

[Joe M. Brown]

Hello all,

I have been looking for a place to get good advice on this. I bought an old house and I am upgrading the kitchen. When we ripped out the old carpet, we found that the sub floor is 1/2 inch ply with 5/8 inch particle board on top. In the kitchen they had an additional 1/4 inch ply laid with lanolium glued down on top of it. I took the lanolium and the 1/4 inch out.

I have all new cabinets to install along with new appliances and most likely a granite counter and possibly full hardwood flooring.

My question is should I be worried about load capacity. I am converting an old laundry room and old kitchen into one big kitchen. I know if we put in hardwood floors I will need to pull up the particle board and lay plywood down. Should I simply do this anyway?

Should I be worried about load putting in granite, more cabinets, and hardwood? The joists are 2x10, spaced 16 inches. I had to rip out some of the sub floor to get at plumbing and electrical in order to reroute for the new sink and lights. The 1/2 inch is just way to thin. I planned on putting back in 1/2 + 5/8 plywood in those areas to meet the height of the old particle board. My question is should I just replace ALL of the particle board? Or should I go a step further and pull out the whole subfloor in these areas and replace it with 3/4 inch or 1 inch thick ply and get rid of the 2 layer subfloor all-together?

Thanks for any help you can provide.

[Joe Funderburk, CMI]

I wouldn't have "particle board" in any area where water could be an issue. If you mean OSB, then that would be OK.

[Christopher Currins]

Proper Subfloors For Hardwood Flooring

[Robert Ernst]

I've built several cabinet over the years and laid floors. I would take it right down to the sub-floor. Get rid of the particleboard. It's a sponge and if it gets wet it will swell and could mold. The min sub-floor and underlayment I like to see if 1 1/8". You will have to use lots of screws to hold the sub-floor and underlayment together. I prefer 1 1/8" T&G sub-floor and then you can put some paper down and the flooring. You can always call your flooring contractor and if they are good they should have good advice.